The present disclosure generally relates to a method of forming a Group III nitride structure on a substrate, and more particularly to a method of forming a planar Group III nitride material structure on a patterned substrate. The present disclosure also relates to a semiconductor structure including a Group III nitride material structure which has a planar uppermost surface and a corrugated bottommost surface.
Group III nitride materials are a unique group of semiconductor materials which can be used in a wide variety of applications including, for example, optoelectronics, photovoltaics and lighting. Group III nitride materials are composed of nitrogen and at least one element from Group III, i.e., aluminum (Al), gallium (Ga) and indium (In), of the Periodic Table of Elements. Illustrative examples of some common Group III nitrides are AlN, InN, GaN, GaAlN, and GaAlInN. By changing the composition of Al, Ga and/or In within a Group III nitride material, the Group III nitride material can be tuned along the electromagnetic spectrum; mainly from 210 nm to 1770 nm. This spectrum includes the visible light emitting diode (LED), which is more than a 10 billion dollar industry with a forecasted double digit yearly growth rate. This continuous growth in LED demand enables the infrastructural build-up for the growth and fabrication of Group III nitride based semiconductor devices.
For GaN integration on silicon, there is a large lattice mismatch value between those two types of semiconductor materials. As such, thick (on the order of 2-3 μm) strain-compensation buffer layers are grown on silicon prior to device formation. Such buffer deposition requires temperature cycling so as to maintain the stain level of the gallium nitride material which increases the growth time and wastes materials. This “thick and engineered” buffer layered approach increases the cost and is one of the main bottlenecks for forming epitaxial gallium nitride materials on silicon substrates.
In view of the above, there is a need for providing a method for epitaxial forming a Group III nitride material on a surface of a silicon substrate that avoids the formation of the “thick and engineered” buffer layers and thus reduces the cost of forming epitaxial Group III nitride materials on silicon substrates.